The invention relates generally to a double break disconnect switch for high voltage applications and, more particularly, to a double break disconnect switch having fixed jaws and a switch blade assembly having a macro swinging movement relative to the jaws and arranged for a rotational movement with respect to its longitudinal axis upon contact with the fixed jaws to effect closing and opening of the switch.
High voltage switches of this type customarily employ round tubular blades which rotate on their long center axis to achieve the contact pressure developing or relieving for opening or closing of the switch. Because of restrictions to movement that may develop because of causes such as ice build up between the fixed jaws and the switch blade assembly or debris large forces are often necessary to initially open or finally close the switch.
Many such switches on the market today employ arrangements such as a beveled gear approach for rotational movement of the switch blade assembly with respect to its longitudinal axis. Such an arrangement is disclosed in U.S. Pat. No. 2,810,799 issued to Robert D. Carmichael, et al. on Oct. 22, 1957. The Carmichael device uses cooperating gear teeth for rotation of the switch blade about its longitudinal axis with a spring bias. Another switch using a different arrangement for rotation of the switch blade assembly with respect to its longitudinal axis is disclosed in U.S. Pat. No. 3,134,865 issued to Joseph Bematt on May 26, 1964. The Bematt device discloses a switch using a pressure member to engage a V-shaped cam which includes circular detents to lock the blade assembly in desired position. And still another such switch arrangement is disclosed in U.S. Pat. No. 4,078,162 issued to John L. Turner on Mar. 7, 1978. The Turner switch utilizes a blade lock that uses a pivotally mounted latch on a remote terminal at the switch jaw which includes a hook-like portion spring biased downwardly into latching position with respect to the end portion of the blade and is rotatable out of latching position by engagement with the latch of an arm carried by the blade when the contact lug is rotated out of engagement with the remote terminal and is formed with an extension engageable with the blade mounted latch operating arm for opening the latch as the blade approaches closed position. Yet another such switch arrangement is disclosed in U.S. Pat. No. 1,695,868 issued to Joseph Stolz on Dec. 18, 1928. The Stolz switch uses an operating mechanism which includes a pair of upright perforated lugs with an inclined face formed on a plate carried by a rotating insulator which engages lugs on a sleeve that surrounds the blade to cause rotation of the blade about its longitudinal axis.
Although the foregoing arrangements are functional there still exists a need and it is therefore an object of this invention to provide an optimized arrangement for rotational movement of the switch blade assembly with respect to its longitudinal axis.